p–n junction

About: p–n junction is a research topic. Over the lifetime, 7701 publications have been published within this topic receiving 108890 citations. The topic is also known as: p-n junction.

Origin of conductivity and low-frequency noise in reverse-biased GaN p-n junction

Abstract: We study the origins of conductivity and low-frequency noise in GaN p-n junctions under reverse bias. Carrier hopping through defect states in the space charge region is identified as the main mechanism responsible for low bias conductivity. Threading dislocations appear the most likely source of such defect states. At higher bias hopping is supplemented with Poole–Frenkel emission. A relatively high level of 1/f-like noise is observed in the diode current. The bias and temperature dependencies of the noise current are investigated.

Gate-tunable diode and photovoltaic effect in an organic–2D layered material p–n junction

Abstract: The semiconducting p–n junction is a simple device structure with great relevance for electronic and optoelectronic applications. The successful integration of low-dimensional materials in electronic circuits has opened the way forward for producing gate-tunable p–n junctions. In that context, we present here an organic (Cu-phthalocyanine)–2D layered material (MoS2) hybrid p–n junction with both gate-tunable diode characteristics and photovoltaic effect. Our proof-of-principle devices show multifunctional properties with diode rectifying factors of up to 104, while under light exposure they exhibit photoresponse with a measured external quantum efficiency of ∼11%. As for their photovoltaic properties, we found open circuit voltages of up to 0.6 V and optical-to-electrical power conversion efficiency of 0.7%. The extended catalogue of known organic semiconductors and two-dimensional materials offer the prospect for tailoring the properties and the performance of the resulting devices, making organic–2D p–n junctions promising candidates for future technological applications.

Enhanced X-ray Sensitivity of MAPbBr 3 Detector by Tailoring the Interface-States Density

Abstract: An important factor for the high performance of light-harvesting devices is the presence of surface trappings. Therefore, understanding and controlling the carrier recombination of the organic–inorganic hybrid perovskite surface is critical for the device design and optimization. Here, we report the use of aluminum zinc oxide (AZO) as the anode to construct a p–n junction structure MAPbBr3 nuclear radiation detector. The AZO/MAPbBr3/Au detector can tolerate an electrical field of 500 V·cm–1 and exhibit a very low leakage current of ∼9 nA, which is 1 order of magnitude lower than that of the standard ohmic contact device. The interface state density of AZO/MAPbBr3 contact was reduced from 2.17 × 1010 to 8.7 × 108 cm–2 by annealing at 100 °C under an Ar atmosphere. Consequently, a photocurrent to dark current ratio of 190 was realized when exposed to a green light-emitting diode with a wavelength of 520 nm (∼200 mW·cm–2). Simultaneously, a high X-ray sensitivity of ∼529 μC·Gyair–1 cm–2 was achieved under 80 kVp X-ray at an electric field of 50 V·cm–1. These results demonstrate the use of surface engineering to further optimize the performance of MAPbBr3 detectors, which have many potential applications in medical and security detection with low radiation dose brought to the human body.

Constant-voltage diode for over-voltage protection

Abstract: A constant-voltage diode has a first semiconductor region of a first conductivity type, an adjoining semiconductor region of a second conductivity type, a third semiconductor region of the second conductivity type adjoining the second semiconductor region, and a fourth semiconductor region of the first conductivity type partially surrounded by the second semiconductor region. At low reverse biases between a cathode electrode and an anode electrode, the behavior of the device is determined by the pn junction between the first and second semiconductor regions. As the reverse biasing increases, the depletion layers of that junction will reach the fourth semiconductor region, but the reverse bias at this time is insufficient to break down that junction. A further increase of reverse bias causes breakdown of the pn junction between the third and fourth semiconductor regions. This effect is achieved by suitable impurity concentrations in the semiconductor regions. A plurality of fourth semiconductor regions may be provided, and a bi-directional structure can be obtained by providing a polarity reversed structure with the first semiconductor region in common.